This invention relates to the structure of centrifuge vacuum chambers, and particularly to the means for closing and securing such a chamber during operation of the centrifuge.
As shown in Jacobson and Taylor U.S. Pat. No. 3,391,862, issued July 9, 1968 and assigned to the assignee of this application, a centrifuge vacuum chamber may have a top opening which is closed by sliding a door horizontally into position to provide a sealed cover for the opening. In order to protect the sealing element which encircles the opening, the door should be lowered onto the seal after, or raised above the seal before, its horizontal motion occurs.
One of the design requirements for safety of such a centrifuge chamber is provision of means for preventing fragments, or "shrapnel", from flying out of the chamber in the event of an explosion inside the chamber. Such an explosion might be caused by rotor failure due to corrosion of the aluminum rotors. Since the design of the horizontally movable door requires some vertical clearance in order to permit the door to be lowered onto the sealing member, an explosion inside the chamber will lift the door sufficiently to permit fragments to escape around the periphery of the opening.
Heretofore, the solution of this "shrapnel" problem has been the provision of a "shrapnel shield", secured to and fully enclosing the entire open end of the space provided for the door. Such a shield is cumbersome and bulky, particularly because it must provide a large enough enclosure to allow for the horizontal movement of the door required to fully uncover the chamber opening. The phantom lines shown in FIGS. 1 and 3 of the drawings herein illustrate a shrapnel shield of the type which has been in use for a number of years prior to this invention.